Computer Fan Cable Pinout

A pwm capable fan is usually connected to a 4 pin connector pinout.

Rechargeable fan egypt. A four pin connector is a little different than the three pin connector since it has the extra fourth wire used for controlling and sending signals to the fan which likely has a chip on it that tells it to slow down or speed up in addition to the other wires the three pin connector has. Fans and on board fan headers are backwards compatible. The 3 pin senses fan rpm revolutions per minute.

A fan with a 3 pin power connector may be easilly fitted into desktop board with a 4 pin fan header. And some dells use standard wiring. A 4 wire cpu motherboard fan is a standard brushless dc bldc fan but has four wires extending from the casing.

The tacho signal from the fan sinks to ground for every revolution the input on the motherboard is pulled high. Desktop board has a 4 pin fan header. Vice versa it is possible to use old 3 wire fan on new board with 4 wire header but with limited possibility of pwm control depending on board logic.

4pin pwm on 3 pin. Teoretically is possible to use 4 wire fan like 3 wire on the board with 3 wire connector. When no revolutions are sensed by the system an audio alarm or no system boot will occur warning the user or preventing proccessor overheating and burnout.

Proper fan connector placement is shown in the figures below. There is no fan control. Ground 12 v sense control.

3 pin fan and 4 pin motherboard connector compatibility. It has 5 pins but only 4 wires are used. Dell does not publish this.

Fan uses control ic bd6709nfs from rohm company. Each of these wires serves a specific purpose. Fans and on board fan headers are backwards compatible.

When using a 3 pin power connector with a 4 pin fan header the fan will always be on. Fan has a 3 pin power connector. The sense pin is used to relay the rotation speed of the fan and the control pin is an open drain or open collector output which requires a pull up to 5 v or 33 v in the fan.

3 pin connectors are usually used for the smaller chassis fans with lower power consumption while 4 pin. Fan has a 3 pin power connector. There is no fan control.

When using a 3 pin power connector with a 4 pin fan header the fan will always be on. Desktop board has a 4 pin fan header. Of course all you need is the red and black wire to run your computer fan but if you didnt know what the extra wires are for this video may help you out.

Fans with three pin connectors must be used on 3 pin cpu fan pinouts. Update october 13 2008. Dell sometimes swaps the wires around so that you will fry a dell fan on standard and the other way round.